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Session B11: Inertial Navigation Technologies

Near NAV-Grade SAFRAN MEMS Gyro Improves SWaP with New ASIC and Ceramic Packaging
Jean-Daniel Emerard, Jean-Sébastien Macé, Frederic Fretouly, Baptiste Soyer, Safran Electronics&Defense; Rob Compton, Safran Federal Systems; Alexandre Lenoble, Julien Auger, Safran Electronics&Defense
Location: Ballroom E
Alternate Number 1

Safran Federal Systems is a United States Proxy company for Safran Electronics & Defense, a world leader in Inertial Navigation Systems (INS) for both civil and military applications. Over the last five years, Safran has achieved a major technological breakthrough by developing an axially symmetric MEMS-based miniature resonator gyroscope (MRG) with exceptionally well-matched vibrational modes, leading to exceptionally low drift and unrivaled stability over temperature for a MEMS gyroscope [1,2].
Although fabricated in a planar MEMS form factor, the MRG is topologically similar to Safran’s flagship hemispherical resonator gyroscope (HRG), and can operate in a rate-integrating or whole-angle operating modes [3]. This paper presents the next stage of product development, with the design and implementation of an “MRG Core” that integrates an analog Application Specific Integrated Circuit (ASIC) into a custom ceramic package, along with the vacuum-sealed Silicon Gyro die.
The integrated circuit notably includes all of the actuation and detection analog electronics and the analog to digital interfacing. With 50mW typical power consumption, and 4.5mm on a side, the ASIC provides exceptional SWaP improvement for this high-performance architecture. With the MEMS die, the ASIC and a voltage reference, the MRG Core tightly integrates all of the critical functions for gyroscope performance which enables individual calibration and leads to a straightforward manufacturing process for the resulting Inertial Measurement Unit.
For characterization purposes, this new MRG Core has been mounted and tested in an IMU configuration where it has been paired with Safran’s navigation grade silicon accelerometer [4]. Typical compensated bias repeatability over the entire operational temperature range is better than 0.1°/h RMS, and angular random walk is 0.003°/?h. Both scale factor linearity and thermal stability have been measured under 30ppm RMS. These results are consistent with previously published performance with discrete electronics, and now extend those previous measurements to validate the exceptional performance of this new, low SWaP integrated gyro and ASIC configuration.
References
[1] J-S Macé, A. Jeanroy, J. Auger, F. Fretouly, M. Colin, A. Berthelot, C. Poulain, 5èmes Journées Micro & Nano Technologies pour l'Inertiel (2019).
[2] JS. Macé, C. Kergueris, F. Fretouly, J. Auger, Y. Lenoir, F. Delhaye, JD. Emerard, IEEE Inertial 2022.
[3] Fabrice Delhaye, 5th IEEE International Symposium on Inertial Sensors and Systems, (2018).
[4] Daniel Marjoux, IEEE - DGON - Inertial Sensors and Systems 2020, Braunschweig, Germany

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